Feed system for apparatus for performing operations on sheet material

ABSTRACT

A feed bar assembly for apparatus for performing operations on sheet material including a feed station wherein a plurality of sheets are supported in a stack and means for reciprocating the feed bar to advance single sheets to a pair of feed rolls comprising an elongated bar and a plurality of feed fingers mounted along the length of said bar, each of said fingers including a plate member and a feed clip mounted on said plate member having a pickup portion adapted to engage an edge of one sheet at the bottom of the stack to advance the same to the feed rolls and actuator means adapted to pivot said feed fingers upwardly to insure positive engagement of each of said feed fingers with the edge of said one sheet, said actuator means including a leaf spring secured at one end to said feed bar and at its opposite free end engaging said plate member and a hydraulic actuator assembly engaging said leaf spring.

United States Patent 1 Henc [54] FEED SYSTEM FOR APPARATUS FOR PERFORMING OPERATIONS ON SHEET MATERIAL [76] Inventor: Edward V. Henc, Promisedale Farm, Boot Road, R.D. No. 2, Ma]- vern, Pa. 19355 [22] Filed: June 30, 1971 21 Appl. No.: 158,501

[52] US. Cl. ..271/44 R, 271/32 [51] Int. Cl. ..B65h 3/24 [58] Field of Search ..271/44 R, 44 A, 42, 54, 14, 271 /32 [56] References Cited UNITED STATES PATENTS 1,959,854 5/1934 Cameron ..271/44 R 2,705,143 3/1955 Greenwood .....271/44 R 3,002,751 10/1961 Wheeler et al. .....27l/44 A 3,588,093 6/1971 Ward et a]. ..271/44 A Primary Examiner-Evon C. Blunk Assistant Examiner-Bruce H. Stoner, Jr. Attorney-Howson & Howson [57] ABSTRACT A feed bar assembly for apparatus for performing operations on sheet material including a feed station wherein a plurality of sheets are supported in a stack and means for reciprocating the feed bar to advance single sheets to a pair of feed rolls comprising an elongated bar and a plurality of feed fingers mounted along the length of said bar, each of said fingers including a plate member and a feed clip mounted on said plate member having a pickup portion adapted to engage an edge of one sheet at the bottom of the stack to advance the same to the feed rolls and actuator means adapted to pivot said feed fingers upwardly to insure positive engagement of each of said feed fingers with the edge of said one sheet, said actuator means including a leaf spring secured at one end to said feed bar and at its opposite free end engaging said plate member and a hydraulic actuator assembly engaging said leaf spring,

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FEED SYSTEM FOR APPARATUS FOR PERFORMING OPERATIONS ON SHEET MATERIAL The present invention relates to improvements in machines for performing cutting, creasing, printing, embossing or like operations on sheet material such as corrugated board or the like. Morespecifically, the present invention is directed to an improvement in blank feeding assemblies for such machines.

The machines comprise a main frame having a feed table at one end for a plurality of work sheets or blanks arranged in a stack, means for maintaining the box blanks in a vertical stack, feed means adapted for reciprocating movement for advancing the lowermost sheet from the stack to a pair of feed rolls which in turn advance the sheet one at a time through the machines for other operations such as cutting, creasing, printing, embossing or like operation.

The present invention is designed as an improvement on the feed system shown in a pending application entitled Air Cushioned Kicker Feed Bar, Ser. No. 11,596, filed Feb. 16, 1970. In this system the feed mechanism comprises an elongated bar mounting a plurality of spaced feed fingers, each feed finger including a pivotally mounted plate member and a feed clip mounted on the plate member having a pickup portion adapted to engage an edge of one at the bottom of the stack to advance the same to the feed rolls and hydraulic actuator means adapted to pivot said feed fingers upwardly to insure positive engagement of each feed finger with the edge of the sheet. While this system is generally effective for the purposes intended, the feed system of the present invention provides a more positive feeding action with all types of sheets, including some which have extreme warps. To this end, the present invention provides a plurality of feed fingers and a leaf spring for each of the feed fingers and hydraulic actuator means engaging the leaf spring to normally bias the feed fingers into a position for positive engagement with the edge of the sheet. The feed system of the present invention further includes a suction hold-down unit disposed centrally of the feed table having an upper face preferably disposed at a slight angle to the feed table whereby each sheet, as it is being fed, is positively held at the forward edge to insure passage through the gates adjacent the feed rolls. In accordance with this embodiment of the invention, the feed bar has an offset center portion to provide a lower profile. By this arrangement, the side portions of each sheet extend slightly below the suction hold-down pan to insure a positive gripping action by the feed fingers as well as a firm gripping action by the suction holddown unit.

The feed fingers are mounted on a feed bar and are preferably disposed adjacent the lead edge thereof so that a large area of each sheet is exposed to the suction area, thereby insuring proper feeding of the blanks. Additionally, the leaf springs which extend back to the rear edge of the feed bar act as a stack stabilizer. This is an important feature, particularly when feeding short sheets, and insures against tilting of the stack which may occur during the stroke of the feed bar. As noted above, the top face of the suction hold-down unit is disposed at an angle which is more in line with the angle of the feed fingers to insure more reliable feeding and preclude jamming of the sheets or boards. Additionally, in the overhand area on either side of the suction hold-down unit, there is a negative pressure which also aids in maintaining the blank being fed in a proper position to pass the front gates of the machine.

These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth with reference to the accompanying drawings, wherein:

FIG. 1 is a plane view of the feed section of a machine for performing cutting, creasing, printing, embossing or like operations on sheet material showing a feed system in accordance with the present invention;

FIG. 2 is a sectional view taken on lines 2-2 of FIG. 1; 7

FIG. 3 is an enlarged detail partly in section of one of the feed finger assemblies;

FIG. 4 is a plan view thereof;

FIG. 5 is a schematic illustration of the electrical and hydraulic circuitry for the feed bar assembly;

FIG. 6 is a perspective view of a machine incorporating another embodiment of feed system in accordance with the present invention; and

FIG. 7 is a transverse sectional view taken on lines 7-7 of FIG. 6.

Referring now to the drawings, particularly to FIGS. 1 and 2 thereof, there is shown the feed section of the machines for performing cutting, creasing, printing, embossing or like operations on sheet materials, for example box blanks B. The feed section broadly designated by the numeral 10 includes a feed table 12 on which a stack of blanks B are supported in position to be fed through the machine, and a pair of feed rolls 14 rotatably journalled between the side walls of the main frame and which advance a single sheet at a time through the machine for performance of various operations on the box blank B, for example cutting, creasing, printing or embossing. As is conventional, the feed table 12 has means for maintaining the stack of box blanks accurately in a predetermined position on the table including a pair of adjustable side guides 16 and 17, a pair of back stop members 18, each having a shelf on which the stack is supported in the angular position illustrated in FIG. 2, and front stops 20 which are adjusted so that the gap between the lower edges thereof and the confronting surface of the: feed table is just sufficient for passage of only one of the blanks therethrough at a time.

Each of the feed fingers 32 comprises a generally rectangular plate member 50 pivotally connected to the forward edge of the feed bar as at 52. Each of the plate members has a downwardly curved rear portion 54 which mounts an arcuate feed clip 56 having a pickup face portion 58 preferably disposed tangent to the radius of the rear terminal portion to grip the rear edge of the sheet during the feeding operation.

Each of the feed fingers 32 is normally disposed at an angle to the upper surface of the feed bar 30 by means including a leaf spring 57 and an actuator assembly 59. In the present instance, each elongated leaf spring 57 has an offset rear terminal portion 63 of inverted L- shaped cross section to provide means for securing the leaf springs adjacent the rear edge of the feed bar. The forward end of each of the leaf springs 57 mounts a roller 65 which engages the lower side of the plate member 50. Each of the leaf springs is engaged along its length by means of an actuator mechanism 59 generally similar in construction and arrangement to the actuator mechanism 59 described in the previous embodiment. Thus, the actuator mechanism consists of a block-like housing 60 having a generally cylindrical piston chamber 62 formed therein within which is mounted a piston member 64. The piston chamber 62 is formed by a cavity extending inwardly from the bottom face of the block-like housing. In the mounted position the piston chamber is sealed by an O-ring 68 mounted in a circumferentially extending groove 66 in the lower face of the housing. The piston 64 is an enlarged piston portion with a groove therein to mount a sealing ring 70, the lower face of the piston having a projection 72 so that the piston does not block the inlet port 76 when it is in the lower position. The piston includes a pin-like projection 80 extending from its front face which engages through an opening 82 in the upper wall of the housing 60 and normally engages the leaf spring at the point 83. Each of the housings mounts, in the present instance, a T-fitting 100 which connects the inlet port to a common line 102 attached to a suitable source of fluid pressure, for example high air pressure, the line 102 being connected in a circuit as shown in FIG. 5.

The circuit includes a solenoid control valve 104, a pressure regulator 106 and a pressure gauge 108.

Referring now by way of example only to the particular form of circuit arrangement illustrated in FIG. 5, the circuit shown therein provides the capability of skipfeed operation mentioned hereinafter. To this end, the solenoid 120 of the solenoid valve 104 is provided with a pair of control leads 122 and 124 which are connected to the power line terminals 128 and 129 respectively when the feed control switch 130 is in its regular feed position; more particularly, solenoid lead 124 is connected directly to power line terminal 129, while control lead 122 is connected to the other power line terminal 128 by way of the contacts 134 and 136 of switch 130 when the switch arm 138 thereof is in its lower or regular feed position as shown in FIG. 5. Under these conditions the solenoid valve 104 remains operated at all times, so as to supply air pressure through regulator 106 to the hydraulic actuator mechanism 59 for normal feed operation as described hereinabove. Supply of power to terminals 128 and 129 may be controlled by the same main control switch (not shown) that supplies power to the rest of the machine.

Feed control switch 130 has two positions other than the regular-feed position described above, namely an off position in which the switch arm 138 is connected to switch contact 140 and the skip" position in which the switch arm is connected to switch control 142. When the switch is in its off position, the connection between power line terminal 128 and solenoid control lead 122 is opened, whereby the solenoid is deactuated and the hydraulic valve closed, so that the kick bar 30 remains deactuated and feed is discontinued.

In the skip position of switch 130, powerline terminal 128 is connected to control lead 122 of solenoid 120 by way of the controlled terminals 148 and 150 of the flip-flop relay 152. The latter relay is of a known commercially-available type having two stable states, a first or high-conduction state in which contact 148 is effectively connected directly to contact 150 to pass current through the relay, and a second or low-conduction state in which the latter two terminals are effectively open-circuited from each other. The flip-flop relay 152 is further characterized by a pair of control terminals 156 and 158 having the property that a control pulse supplied between these terminals is effective to change the flip-flop relay from either of its conduction states to the other, and the next-subsequent control pulse is operative to flip the relay back to its first conduction state. Such devices being well known in the art, it will be unnecessary to describe herein the internal connections, arrangements and details thereof.

The latter pair of control terminals 156 and 158 are connected between the power-line terminals 128 and 130, terminal 158 being connected directly to terminal 129 while control terminal 156 is connected to powerline terminal 128 through the impulse switch sensor 164 and the arm 138 of switch when the latter arm is in its upper or skip position. When the entire machine is operating, a control pulse is applied between the relay control terminals 156 and 158 each time the impulse switch sensor 164 is closed. As described hereinbefore, the latter switch is closed each time the linkage 38a moves forward during its normal cycle of operation. Accordingly, it will be appreciated that when the feed control switch 130 is in its skip position, current will be supplied through flip-flop relay 152 to hold'solenoid valve 104 open during a given cycle of operation of the feeder bar 30. The operation of the feed bar will then close the impulse switch sensor thereby to apply a control pulse between control terminals 156 and 158 of relay 152 and change it to its non-conductive state; during the next successive cycle of operation of the feeder bar, no current will be supplied to solenoid valve 104. Accordingly, valve 104 will be closed, so that the hydraulic actuator mechanism 59 is deactuated. During the next stroke of the feeder bar, the impulse switch sensor 164 will again be operated and will cause a voltage pulse to be applied between control terminals 156 and 158 of the relay 152, to return the flip-flop relay to its high-conduction state, thereby again opening solenoid valve 104 and reactuating the hydraulic actuator mechanism 59 so as to feed the next subsequent sheet into the feed rolls.

In overall operation then, with the switch 130 in its lower position normal operation is obtained whereby a sheet is fed into the feed rolls during each cycle of operation of the feeder bar 30. When the latter switch is in its off position, no such feeding occurs at all; and when the latter switch is in its skip position, the hydraulic actuator mechanism 59 is actuated and a sheet delivered to the feed rolls only for every other cycle of the feeder bar. I

Accordingly, in the operation of the system described above, assume that there is a stack of boards at the feeding station which are supported at a predetermined height above the feed table in the manner illustrated in FIGS. 1 and 2. For single feed operation, the operator positions the selector switch 130 for regular feed and starts the machine by actuating the main switch. During reciprocating movement of the feed bar through the linkage 38a, the feed clips 56 engage the lowermost blank to advance the same into the nip of the feed rolls l4. Initially, the solenoid valve 104 is open, thereby pressurizing the actuators 59 to move the spring fingers into pressure-applying relation with the lowermost blank in the stack. Skip feed operation is controlled through selector switch 130. It is noted that in the present system, the combination of the leaf spring and the actuator assemblies insures a positive gripping action of each of the fingers during the feeding operation to preclude the possibility of cocking the lowermost blank which may cause the machine to jam.

It is noted that the leaf springs serve as a stack stabilizer and support the blanks when the feed bar is actuated in the manner shown in FIG. 3. This is a particularly important feature when feeding short blanks to prevent the stack from tilting.

There is illustrated in FIGS. 6 and 7 a combination feed assembly and sheet hold-down unit in accordance with the present invention. The hold-down unit generally designated by the numeral 300, is mounted on the feed table 302 of the apparatus. The unit 300 is generally of rectangular shape and is aligned with the central axis of the machine so that the lead edge is disposed adjacent the front gates 306. The hold'down unit is a hollow pan assembly having a tapered top panel 310 which is disposed at a downwardly inclined angle relative to the feed table, and has a plurality of openings 312 arranged in rows therein adjacent the front edge of the unit. The pan assembly has a manifold section 314 adjacent the rear end which is connected through a line 320 to a suitable source of vacuum, for example the vacuum system present in a plant using this type of equipment.

The feed assembly in the present instance comprises an elongated feed bar 330 having an upwardly offset center portion 332 overlying the hold-down unit 300 and a plurality of feed fingers 334 mounted on the bar. The feed bar assembly is adapted for reciprocating movement to feed blanks by the same system as described previously. The feed fingers are generally similar in construction and operation to those described in the principal embodiment of the invention. In the present instance, the feed fingers 334a are secured at an angle to a tapered lead edge 335 of the center section 332 of the feed bar and the feed fingers 334k mounted on the outboard sections 340a and 340b of the feed bar are pivotally mounted to the bar. Each of these feed fingers has an actuating mechanism 341 suitably connected by a T-fitting to the feed line 350 which in turn is connected to a suitable source of fluid pressure, for example high pressure air. The actuator 341 is identical in construction to the actuator 59. This line 350, as in the previously described embodiments, is connected to a circuit of the type shown in FIG. 5 to provide for regular and skip feed operation as desired.

It has been foundthat the particular feed assembly and sheet hold-down unit described above provides several advantages in the operation of apparatus for feeding sheet material such as box blanks B. As described previously, these blanks are arranged in a stack so that the lowermost blank engages the feed fingers on the feed bar and are advanced one at a time into the feed rolls upon reciprocating movement of the feed bar 330. In the present instance, the forward portion of the lowermost blank is held flat during the feeding operation by the operation'of the vacuum pan assembly. In this regard, the angled configuration of the top face of the pan in combination with the offset feed bar and feed finger arrangement insures trouble-free operation even with box blanks that may be considerably warped. More specifically, it has been found that this arrangement provides a lower profile and the overhang on either side of the pan. of the blanks B provides a better gripping action for the feed fingers and insures a positive hold-down by the vacuum system. As noted above, the vacuum chamber at the rear of the pan provides a constant vacuum, and the overhang of the blanks creates a negative pressure to firmly support the lowermost blank against the hold-down unit. Further, existing machinery may be easy and economically modified to incorporate the hold-down unit and feed bar assembly described above.

I claim:

1. A feed bar assembly for apparatus for performing operations on sheet material including a feed station wherein a plurality of sheets are supported in a stack and means for reciprocating the feed bar to advance single sheets to a pair of feed rolls comprising an elongated bar and a plurality of feed fingers mounted along the length of said bar, each of said fingers including a plate member and a feed clip mounted on said plate member having a pickup portion adapted to engage an edge of one sheet at the bottom of the stack to advance the same to the feed rolls and actuator means adapted to pivot said feed fingers upwardly to insure positive engagement of each of said feed fingers with the edge of said onesheet, said actuator means including a leaf spring secured at one end to said feed bar and at its opposite free end engaging said plate member and a fluid actuator assembly engaging said leaf spring.

2. A feed bar assembly as claimed in claim 1 wherein each of said feed fingers comprises a plate member pivotally connected to said bar, each of said plate members having a downwardly curved rear portion and an arcuate feed clip mounted on the curved rear portion having a pickup face portion disposed tangent to the radius of the rear terminal portion.

3. A feed bar assembly as claimed in claim 1 wherein said fluid actuator assembly comprises a housing having a piston chamber therein, a piston mounted in said chamber having an actuating pin projecting from one face thereof adapted to engage said leaf spring and fluid means for selectively pressurizing said chamber to pivot said feed finger in a direction wherein it engages the edge of the lowermost sheet.

4. A feed bar assembly as claimed in claim I including a fluid pressure system and means connecting the system to all of the actuator means for the feed fingers.

5. A feed system for apparatus for performing operations on sheet material including a feed station including a flat feed table wherein a plurality of sheets are supported in a stack comprising reciprocating feed means for advancing single sheets to a pair of feed rolls including an elongated bar and a plurality of feed fingers mounted along the length of the bar and a holddown unit at the feed station consisting of a hollow housing having an upper wall inclined rearwardly relative to the feed table from the feed rolls, a plurality of openings and a manifold connected to a source of vacuum.

6. A feed system as claimed in claim wherein said feed bar has an upwardly offset center portion overlying the hold-down unit. 

1. A feed bar assembly for apparatus for performing operations on sheet material including a feed station wherein a plurality of sheets are supported in a stack and means for reciprocating the feed bar to advance single sheets to a pair of feed rolls comprising an elongated bar and a plurality of feed fingers mounted along the length of said bar, each of said fingers including a plate member and a feed clip mounted on said plate member having a pickup portion adapted to engage an edge of one sheet at the bottom of the stack to advance the same to the feed rolls and actuator means adapted to pivot said feed fingers upwaRdly to insure positive engagement of each of said feed fingers with the edge of said one sheet, said actuator means including a leaf spring secured at one end to said feed bar and at its opposite free end engaging said plate member and a fluid actuator assembly engaging said leaf spring.
 2. A feed bar assembly as claimed in claim 1 wherein each of said feed fingers comprises a plate member pivotally connected to said bar, each of said plate members having a downwardly curved rear portion and an arcuate feed clip mounted on the curved rear portion having a pickup face portion disposed tangent to the radius of the rear terminal portion.
 3. A feed bar assembly as claimed in claim 1 wherein said fluid actuator assembly comprises a housing having a piston chamber therein, a piston mounted in said chamber having an actuating pin projecting from one face thereof adapted to engage said leaf spring and fluid means for selectively pressurizing said chamber to pivot said feed finger in a direction wherein it engages the edge of the lowermost sheet.
 4. A feed bar assembly as claimed in claim 1 including a fluid pressure system and means connecting the system to all of the actuator means for the feed fingers.
 5. A feed system for apparatus for performing operations on sheet material including a feed station including a flat feed table wherein a plurality of sheets are supported in a stack comprising reciprocating feed means for advancing single sheets to a pair of feed rolls including an elongated bar and a plurality of feed fingers mounted along the length of the bar and a hold-down unit at the feed station consisting of a hollow housing having an upper wall inclined rearwardly relative to the feed table from the feed rolls, a plurality of openings and a manifold connected to a source of vacuum.
 6. A feed system as claimed in claim 5 wherein said feed bar has an upwardly offset center portion overlying the hold-down unit. 